hash_multimap::hash_multimap

Constructs a hash_multimap that is empty or that is a copy of all or part of some other hash_multimap.

hash_multimap( );
explicit hash_multimap(
   const Compare& _Comp
);
hash_multimap(
   const Compare& _Comp,
   const Allocator& _Al
);
hash_multimap(
   const hash_multimap& _Right
);
template<class InputIterator>
   hash_multimap(
      InputIterator _First,
      InputIterator _Last
   );
template<class InputIterator>
   hash_multimap(
      InputIterator _First,
      InputIterator _Last,
      const Compare& _Comp
   );
template<class InputIterator>
   hash_multimap(
      InputIterator _First,
      InputIterator _Last,
      const Compare& _Comp,
      const Allocator& _Al
   );
hash_multimap(
   hash_multimap&& _Right
);

Parameters

Remarks

All constructors store a type of allocator object that manages memory storage for the hash_multimap and that can later be returned by calling get_allocator. The allocator parameter is often omitted in the class declarations and preprocessing macros used to substitute alternative allocators.

All constructors initialize their hash_multimap.

All constructors store a function object of type Traits that is used to establish an order among the keys of the hash_multimap and that can later be returned by calling key_comp.

The first three constructors specify an empty initial hash_multimap, the second specifying the type of comparison function (_Comp) to be used in establishing the order of the elements and the third explicitly specifying the allocator type (_Al) to be used. The keyword explicit suppresses certain kinds of automatic type conversion.

The fourth constructor specifies a copy of the hash_multimap _Right.

The next three constructors copy the range [_First, _Last) of a map with increasing explicitness in specifying the type of comparison function of class Traits and allocator.

The last constructor moves the hash_multimap _Right.

In Visual C++ .NET 2003, members of the <hash_map> and <hash_set> header files are no longer in the std namespace, but rather have been moved into the stdext namespace. See The stdext Namespace for more information.

Example

// hash_multimap_hash_multimap.cpp
// compile with: /EHsc
#include <hash_map>
#include <iostream>

int main( )
{
   using namespace std;
   using namespace stdext;
   typedef pair <int, int> Int_Pair;
   hash_multimap <int, int>::iterator hm1_Iter, hm3_Iter, hm4_Iter, 
      hm5_Iter, hm6_Iter;
   hash_multimap <int, int, hash_compare <int, greater<int> > 
      >::iterator hm2_Iter;

   // Create an empty hash_multimap hm0 of key type integer
   hash_multimap <int, int> hm0;

   // Create an empty hash_multimap hm1 with the key comparison
   // function of less than, then insert 4 elements
   hash_multimap <int, int, hash_compare <int, less<int> > > hm1;
   hm1.insert( Int_Pair( 1, 10 ) );
   hm1.insert( Int_Pair( 2, 20 ) );
   hm1.insert( Int_Pair( 3, 30 ) );
   hm1.insert( Int_Pair( 4, 40 ) );

   // Create an empty hash_multimap hm2 with the key comparison
   // function of greater than, then insert 2 elements
   hash_multimap <int, int, hash_compare <int, greater<int> > > hm2;
   hm2.insert( Int_Pair( 1, 10 ) );
   hm2.insert( Int_Pair( 2, 20 ) );

   // Create a hash_multimap hm3 with the 
   // allocator of hash_multimap hm1
   hash_multimap <int, int>::allocator_type hm1_Alloc;
   hm1_Alloc = hm1.get_allocator( );
   hash_multimap <int, int> hm3( hash_compare <int, less<int> > ( ), 
      hm1_Alloc );
   hm3.insert( Int_Pair( 3, 30 ) );

   // Create a copy, hash_multimap hm4, of hash_multimap hm1
   hash_multimap <int, int> hm4( hm1 );

   // Create a hash_multimap hm5 by copying the range hm1[_First, _Last)
   hash_multimap <int, int>::const_iterator hm1_bcIter, hm1_ecIter;
   hm1_bcIter = hm1.begin( );
   hm1_ecIter = hm1.begin( );
   hm1_ecIter++;
   hm1_ecIter++;
   hash_multimap <int, int> hm5( hm1_bcIter, hm1_ecIter );

   // Create a hash_multimap hm6 by copying the range hm4[_First, _Last)
   // and with the allocator of hash_multimap hm2
   hash_multimap <int, int>::allocator_type hm2_Alloc;
   hm2_Alloc = hm2.get_allocator( );
   hash_multimap <int, int> hm6(hm4.begin( ), ++hm4.begin( ), less<int>( ), 
      hm2_Alloc);

   cout << "hm1 = ";
   for ( hm1_Iter = hm1.begin( ); hm1_Iter != hm1.end( ); hm1_Iter++ )
      cout << hm1_Iter -> second << " ";
   cout << endl;
   
   cout << "hm2 = ";
   for ( hm2_Iter = hm2.begin( ); hm2_Iter != hm2.end( ); hm2_Iter++ )
   cout << hm2_Iter -> second << " ";
   cout << endl;

   cout << "hm3 = ";
   for ( hm3_Iter = hm3.begin( ); hm3_Iter != hm3.end( ); hm3_Iter++ )
      cout << hm3_Iter -> second << " ";
   cout << endl;

   cout << "hm4 = ";
   for ( hm4_Iter = hm4.begin( ); hm4_Iter != hm4.end( ); hm4_Iter++ )
      cout << hm4_Iter -> second << " ";
   cout << endl;

   cout << "hm5 = ";
   for ( hm5_Iter = hm5.begin( ); hm5_Iter != hm5.end( ); hm5_Iter++ )
      cout << hm5_Iter -> second << " ";
   cout << endl;

   cout << "hm6 = ";
   for ( hm6_Iter = hm6.begin( ); hm6_Iter != hm6.end( ); hm6_Iter++ )
      cout << hm6_Iter -> second << " ";
   cout << endl;

    // Create a copy, hash_map hm7, of hash_multimap hm1 by moving
    hash_map<MyStr, MyInt, hash_compare<MyStr, less_str> >
        hm7(move(hm1));
    cout << "hm7 =";
    for (hm7_Iter = hm7.begin(); hm7_Iter != hm7.end(); hm7_Iter++)
        cout << " " << hm7_Iter -> second;
    cout << endl;
}

Output

hm1 = 10 20 30 40 
hm2 = 10 20 
hm3 = 30 
hm4 = 10 20 30 40 
hm5 = 10 20 
hm6 = 10 
hm7 = 10 20 30 40

Requirements

Header: <hash_map>

Namespace: stdext

See Also

Reference

hash_multimap Class

Standard Template Library